The invention relates to the field of computers, and more specifically to detection of the presence of a connector plugged into a socket. It applies especially, but not exclusively, to detecting the presence of Wake on Lan type connectors (hereinafter referred to as WOL connectors) plugged into the WOL socket of a computer motherboard. (Wake On Lan is a trademark of IBM Corporation)
Power management, and essentially power saving is becoming an important concern for computer manufacturers, inter alia for environmental reasons. It is also a concern for battery-operated computers such as laptop computers. Another concern regarding computers is the remote management of the computers through local area networks or wide area networks. This concern is becoming important as the number of networked computers increases.
FIG. 1 is a representation of the state machine of a computer of the type currently sold by the applicant under the reference HP Vectra VL8. As shown on this figure, the computer may be in five different states. In the first one 1, the computer is off and unplugged, and the power consumption is nil; in a second state 2, the computer is OFF; in this state, the power supply unit is connected to the power supply, and the computer is off. However, the LAN card of the computer is in a sleep mode, that is the LAN is not available, however, the LAN is always powered and the LAN processor in the LAN card scans networks frames. In this state, pursuant to the German Ecolabel, the power consumption of the computer should be less than 5 W. The third state is the ON state, with the computer working; power consumption is then unlimited. The fourth state 4 is the sleep mode, where the functionalities of the computer are degraded; in this state, the power supply unit is on, and the computer as well as its LAN card are in a sleep mode. In this fourth state, pursuant to the recommendations of the US Energy Protection Agency, the power consumption should be less than 30 W. The fifth state 5 is a state where the computer is plugged and off; this state is entered when there is a power failure while the computer is connected to the wall.
The computer passes from the second state to the third one, as symbolised by arrow 6 when the ON/OFF button of the computer is activated to switch the computer on. As symbolised by arrow 7, the computer passes from the fourth statexe2x80x94sleep modexe2x80x94to the third statexe2x80x94ONxe2x80x94when the computer is woken up. This may for instance be the case when the user presses a key on the keyboard of the computer.
For computers connected to a network, it has been suggested to allow both operations to be conducted from the LAN. The corresponding functionsxe2x80x94Remote Power-on or RPO and Remote wake-up or RWU, respectivelyxe2x80x94are implemented on the computers sold by the applicant with the Hewlett-Packard NightDirector features. Remote power-on is the ability to power-on a PC remotely, from the OFF state; remote wake-up is the ability to wake-up a PC from energy saving sleep mode. These functions enable remote management applications to be carried out on remote computers. They involve sending a wake-up or power-on frame on the network; this frame is received and interpreted by the LAN card of the computer.
One LAN card allowing RPO and RWU is the PRO/100 LAN card sold by Intel which includes Wake on Lan capability. For wake-up or remote power-on of the computer, there is provided a WOL connector from the LAN card to the motherboard of the computer. The WOL connector comprises three pins: ground and power (Vccaux) pins, and one pin for a wake signal. Other manufacturers have the same or similar connectors for providing-power from the motherboard, for instance Hewlett-Packard provides on some of its personal computers a NightDirector connector that comprises 5 RPO/RWU related pins, that is ground and power (Vccaux) pins, together with a power on pin, a wake-up pin and a RPO enable pin.
A PC motherboard may comprise more than one socket to accommodate different types of connectors. In the following the term WOL connector will be used to refer both to the Wake on Lan connector (and socket) available from IBM or Intel and to similar connectors or sockets incorporated in the products of other manufacturers.
In the second and fourth states of the state machine of FIG. 1, the power supply unit of the computer is switched off, and the main power supply Vcc of the computer is down. However, the auxiliary power supply Vaux or Vtrickle is available; this auxiliary power supply is used to power the LAN card, through the WOL socket, or through the HP NightDirector socket. Thus, the LAN card may process incoming frames, and the controller may wake-up or power-on the computer.
If a computer comprises more than one LAN cards, and if both cards enable RPO and RWU, more than one motherboard socketxe2x80x94for instance the WOL socket and the HP NightDirector socketxe2x80x94may be provided. In this case, the power supply to the auxiliary power supply may not be sufficient for powering each of the cards. Indeed, due to limitations on the power consumption in the sleep states, the available current on Vaux is usually limited to 700 mA. This problem is explained for instance in the user manual or in the Bios setup of computers sold by the applicant under the reference HP VECTRA VL8. The same problem also exists for any other specification using Vccaux; this is for instance the case for PCI 2.2.
The invention provides a solution to this problem. It ensures that the power consumption of the LAN cards in the computer in the sleep state will remain below the available power.
More generally, the invention provides a solution to the problem of detecting the presence of a WOL connector in a computer. Such a detection may also be useful for purpose other than power management in sleep states.
According to the invention, there is provided a method for detecting the presence of a connector in a socket, said connector keeping a pin of the socket to a a given level, comprising the steps of
activating means for pulling said pin to another level;
determining whether the level on said pin is said given level or said another level; and
detecting the presence of the connector when the level determined on said pin is said given level. In one embodiment of the invention, the means for pulling comprise a resistor and a switch connected in series between said pin and said another level, and the step of activating comprises closing said switch. Prefereably, the pin is wired to a register of a controller, and the step of determining comprises scanning said register. In another embodiment of the invention, the socket is in the motherboard of a computer, and is provided for receiving a connector to a local area network card. In this case, the pin may be a wake-up signal pin.
The invention also provides a method for disabling one of two sockets in a computer board, comprising the steps of:
determining the presence of a connector in one of said sockets, according to the method of one of claims 1 to 5; and
disabling the other of said sockets if a connector is present in said one socket. Preferably, said sockets are in the motherboard of a computer, and are each provided for receiving a connector to a local area network card.
Finally, the invention provides a computer board, comprising a socket for receiving a connector, means for temporarily pulling one pin of said socket to a level, and means for determining the level on said pin. Preferably, the means for temporarily pulling comprise a resistor and a switch connected in series between said pin and said a level. In another embodiment, the pin is wired to a register of a controller, and the means for determining comprises means for scanning said register. Preferably, the socket is in the motherboard of a computer, and is provided for receiving a connector to a local area network card. In another embodiment of the invention, the pin is a wake-up signal pin.